diff --git a/src/phyp/phyp_driver.c b/src/phyp/phyp_driver.c
index fc3e7db0af..3a5eefde5c 100644
--- a/src/phyp/phyp_driver.c
+++ b/src/phyp/phyp_driver.c
@@ -2007,7 +2007,7 @@ phypStorageVolCreateXML(virStoragePoolPtr pool,
         goto err;
     }
 
-    if (voldef->capacity) {
+    if (!voldef->capacity) {
         VIR_ERROR(_("Capacity cannot be empty."));
         goto err;
     }